Sewing machine bobbin case



Aug. 13, 1957 N. E. COLEGROVE 2,802,438

SEWING MACHINE BQBBIN CASE Filed Sept. 8, 1953 79 5f 15 g 15 155/ 3 ,42 25 z? INVENTOR. Mum/W61. 6 Cauemve BY Q I I J W I Arm/vs v.5

United States Patent OfiFice 2,802,438 Patented Aug. 13, 1957 SEWING MACHINE BOBBlN CASE Nathaniel Edward Colegrove, Cleveland, Ohio, assignor -to White Sewing Machine Corporation, Lakewood,

Ohio, a corporation of Delaware Application September 8, 1953, Serial No. 378,961 7 8 Claims. (Cl. 112-231) This invention relates to bobbin cases for sewing machines of the revolving shuttle type and, more particularly, to means for releasably securing such bobbins in the shuttle during sewing operations, means to tension the thread issuing from a bobbin in the case, and means to releasably retain a bobbin in the bobbin case when the latter is removed from the shuttle.

Modern sewing machines of'the lockstitch type conventionally employ a rotary shuttle or hook disposed beneath the material for cooperation with the needle when the latter penetrates the material. In such machines the rotary shuttle carries a thread bobbin which supplies the thread for engagement with the thread carried by the needle, which bobbin is enclosed in a bobbin case removably supported upon the center pin or stud of the shuttle and retained in place by a latching means. It is also necessary or desirable that there be a means to retain the bobbin within the case while placing the latter in or removing it from cooperation with the shuttle. The manner in which this latter function is frequently effected is by providing a projection on the latching means engageable with a portion of the bobbin when the latching means is moved to unlatch the case from the shuttle.

In the prior constructions of the type just mentioned, difiiculty is frequently encountered in releasing the bobbin case from the shuttle due to the fact that an oversized bobbin may have been used, with the result that the bobbin retaining means engaging such bobbin prevents the latching means from moving to the position in which it entirely frees the case from the shuttle. A similar difficulty is frequently encountered for causes other than oversized bobbins, such for example, as a slight cocking of the bobbin in the case, irregularities in the diameter of the flange engaged by the bobbin retaining means, or the like. In all such situations the removal of the bobbin case is a difiicult operation due to the somewhat inaccessible position in which it is generally located, and such removal either requires laborious disassembly of parts or, if the operator be impatient, results in damage to the machine by the forcing apart of the elements which do not readily disengage.

Therefore, an object of this invention is the provision of an improved means for effecting latching of a bobbin case in the rotary shuttle of a sewing machine, together with a means for retaining a bobbin in the case while the latter is unlatched from the shuttle and being placed in, or removed from, cooperation therewith; the operation of the bobbin case latching and bobbin retaining means being independent of the diameter of the bobbin therein thereby insuring complete unlatching of the bobbin case even though an oversized bobbin be therein.

A further object of the invention is the provision of an improved bobbin case latching and bobbin retaining means which is inexpensive to manufacture and assemble and which is concealed when the bobbin case is in place so that the thread issuing from the bobbin can not catch or tangle therewith.

Bobbin cases of the type mentioned above also conventionally employ a thread tensioning means for applying a frictional force or tension upon the thread issuing from the bobbin. Where a conventional latching means, as mentioned above, is utilized upon the bobbin case, the

tension means ordinarily is provided upon the side wall of the case. This has resulted in numerous ditficulties with respect to providing adequate adjustability of the tension since the adjusting means is generally a screw threaded into the side wall of the case. Because the side wall of the bobbin case is relatively thin, very little adjustment is thus provided. and, moreover, the threads of the screw are of necessity quite delicate, are difiicult to manufacture and handle, and are easily stripped. Furthermore, adjustment of such a tensioning means requires the use of a special screw driver or similar tool and, in addition to the fact that the range of tension available is not large, it cannot be. readily determinable. Similar 'clifliculties in securing proper adjustment of thread tension have also been encountered where the tension member is mounted on the end face of the bobbin case by conventional means.

Another object of this invention, therefore, is the provision of an improved thread tensioning means for a bobbin case which means is simple and inexpensive inv construction and may be readily assembled, yet is such that the tension may be easily adjusted through a wide range without the need of tools. a

A further object of the invention is the provision of an improved thread tensioning means as definedin the preceding paragraph and including means for readily indicating the frictional force or tension upon the thread for any adjusted position of the tensioning means.

An additional object of the invention is the provision of an improved bobbin thread tensioning means, as defined above, in which the tension adjustingmechanism may be easily calibrated or regulated to provide different extremes for a predetermined range of adjustability of the frictional forces exerted on the thread issuing from the case.

Another object of the invention is to provide in a sewing machine, which has a rotary shuttle with a bobbin case, an improved means to retain the case on the center pin of the shuttle and an. improved means to adjust the tension of the thread issuing from the bobbin in the case whereby the case is properly .held in place, yet may be easily removed and reinserted, and the tension on the bobbin thread is readily adjustable to optimum value so that sewing operations are improved and facilitated.

The invention further resides in certain novel features of the construction and arrangements of parts of an apparatus and further objects and advantages thereof will be apparent to those skilled in the art to which the invention pertains from the following description of the presently preferred embodiment thereof, described with reference to the accompanying drawings forming a part of this application and in which:

Fig. 1 is a front elevational view of a rotary shuttle provided with a bobbin case constructed in accordance with this invention;

Fig. 2 is a transverse sectional view to an enlarged scale through the shuttle and bobbin case shown in Fig. l, the view being taken substantially on the section indicating line 2-2;

Fig. 3 is a sectional view taken substantially on the line 33 of Fig. 2 and looking in the direction indicated by the arrows, the bobbin case and bobbin being shown in elevation to more clearly illustrate the bobbin case latching and bobbin retaining means;

Fig. 4 is a fragmentary enlarged view of a portion of Fig. 3 more clearly illustrating the bobbin latching and retaining. means;

Fig. 5 is a detached plan view of the adjusting nut member for the thread tension device;

Fig. 6 is a side elevational view of the nut member shown in Fig. 5;

Fig. 7 is a top plan view of the tensioning member 1 employed in the illustrated bobbin case; and

Fig. 8 is a side elevational view of the tensioning member shown in Fig. 7.

Referring now in detail to the drawings, the rotary shuttle 10, shown therein, isconventional, is constructed in a well-known manner, and is adaptedto be rotated by the mechanism ofa sewing machine. Since this construction is well understood by those skilled in the art the details of the shuttle and its connections to the driving mechanism are not here illustrated or described. For the present purposes it is sufiicient to note that the shuttle 1.0 has a recess or opening 11, in which is provided a forwardly extending center pin or stud 12. This pin or stud 12 provides the support for a bobbin case 13, which, in turn, is provided with a thread bobbin 14. As lustrated, the bobbin case 13 is formed of metal and is generally cup-shaped or cylindrical with a substantially planar end face or wall15 which is raised slightly adjacent the periphery, as will be apparent from Fig. 2. The end wall 15 is integral with the cylindrical side wall 16 and a portion of the latter is struck up therefromv to provide an integral projection or finger 17, which is adapted to engage a stationary part of the machine and thus retain the bobbin case stationary during rotation of the shuttle, as is well-known in the art.

The planar face or end wall 15, of the bobbin case 13 has a central opening through which passes a threaded reduced diameter extension 18 of a hollow hub member 19, the interior bore of which is adapted to sleeve over the center pin 12 of the shuttle. The hub member 19 is secured to the end wall 15 of the bobbin by means of a nut 20 threaded on the extension portion, 18 and tightened into engagement with the end wall 15.

here iland 26 engage the inner sides of the bail member tending,

The thread bobbin 14, provided with the thread to be employed in the sewing operation, is adapted to be received Within the bobbin case 13 with the hollow interior of the bobbin supported upon the hub member 19, the length of the side wall ld'of the bobbin case being in the order of the width of the bobbin 14, as will be apparent from Fig. 2. The bobbin case 13 with the bobbin 14 therein is inserted in the shuttle 10 by slipping the hub member 19 over the pin 12 and the bobbin case and bobbin are releasably retained in this position by a resilient means which engages with the center pin or stud 12, thereby preventing displacement of the bobbin case and bobbin during operation 'of'the sewing machine.

In the presently preferred embodiment, the bobbin case latching means comprises a bail-like member 21 which may be formed of stiff wire or the like and is bent to a substantially U-shape with the free ends 22 and 23 thereof turned'inwardly towards each other but spaced apart. These inturned" ends 22 and 23 extend through diametrically directed opening in the hub member 19 adjacent the free end' of the latter and engage within an annular groove 24' provided around the center pin or stud 12 adjacent the base thereof. The bail-like member 21 is' resilient and the ends of the inturned portions 22 and 23 are rounded as will be apparent from Fig. 4. Hence, the bobbin case and bobbin are latched into position by simply pressing inwardly thereon when inserting these members in the shuttle, the ends of the bail member 21 springing apart sufiiciently to accommodate the main body of the pin or stud 12 and then snapping into position within the groove 24, so that the bobbin case and bobbin are 'releasably supported in the shuttle in a manner which permits relative rotation therebetween. The bobbin case and bobbin may be readily removed from the shuttle by pulling outwardly on the bobbin case with sufficient force to displace the ends 22' and 23 of the bail member 21 from the groove 24.

In addition to serving as a means for latching the bobbin case and bobbin in the shuttle 10 the bail member 21 also serves to retain a bobbin 14in the bobbin case when the latter is removed from the shuttle. This is effected by providing the bail member 21 of sufficient length that it may be disposed radially relative to the hub member 19 and extends over an appreciable portion of thefa'ce of the bobbin 14 when thus positioned. As will be apparent from Figs. 2, 3 and 4, the bail member is frictionally retained in this position by having the opposite sides of the hub member 19 milled to substantially planar surfaces 25 and 26 adjacent the inturnedends 22 and 23 of the bail member so that the said planar surfaces 25 It will be apparent from the construction just described.

that the bail member 21 is concealed within the shuttle 10 during operation of the sewing machine and hence can not be caught by, or entangled with, the threadcomr' ing from the bobbin, 14 during the sewing operation.

Furthermore, it will be noted that the bobbin retaining.

and latching functions of this member 21 do not depend upon cooperation with the periphery of the bobbin and hence an oversized bobbin or the like, can not jam the mechanism such as to prevent ready release of the bobbin case.

The thread, indicated at 27, upon the bobbin 14 is adapted to be led therefrom through an opening in the bobbin case and pass over the aforementioned finger or projection 17 for cooperation with the thread carried by the sewing machine needle. In the illustrated construction this is eif'ected by providing an opening in the end face 15 of the bobbin case at the base ofzthe projection or finger 17 through which the thread 27 can be led and directed to pass over the member 17.- The thread thus issuing from the bobbin is placed under tension by a tension member 28 and the force exerted on the thread by this member is adjustable.

In the illustrated embodiment the tension member 28 is resilient and is preferably formed of spring metal with a substantially planar portion 29 extending over the projection or finger 17 and substantially parallel with the latter. The rear portion of the member 28 is enlarged and has a central opening 30 through which the threaded extension 18 of the hub 19 is freely received, see Fig. 2.

This enlarged portion of the tension member is raised above the surface of the end wall 15 by suitable means, as for example, by having spaced angular projections or feet 31 and 32 bent from the plane of the tension member 28 and engaging the end' face or wall 15 of the bobbin case. Preferably, the ends of the extensions, or feet 31, 32 have small extensions receivable in correspondingly spaced recesses or openings such as 33, 34 on the end wall or face 15 to thereby prevent rotation of the tension member 28 relative to the bobbin case.

The force exerted by the tension member 23 upon the thread 27 is variable by means of a nut member 35 which is threaded upon the extension 18 of the hub above the tension member 28 and engageablewith the raised portion thereof to thereby vary the'spacing of the latter from the end wall 15' of' the bobbin case, and thus correspondingly vary the force exerted by the portion 29 upon the thread 27; In order that this engagement of the nut member 35 and the tension member 28 may occur at a predetermined location regardlessv of manufacturing tolerances of the parts, the upper side of'the member 28 is preferably provided with a projection orboss such as 36' formed by an indenting? or dimpling operation on the opposite side of' the member, which projection or boss is engageable by the nut member 35. While only one such projection, or boss 36', is shown it will'be apparent that a plurality of spaced projections or bosses of like nature may be provided.

The nut member 35 is provided with. means for releasably retaining the latter in an adjusted position. and in the preferred embodiment. this. means. is. shown as comprising a resilient member 37 which "is securedto the nut member 35 in any suitable manner,,as for example, by spinning or otherwise upsetting a portionof the nut member upon the resilient member 37, as will be evident from the showing in Fig. 2. Alternatively, the resilient member could be secured to the nut member by soldering, welding or the like, or the nut member and resilient member could be formed integrally, if desired. The resilient member 37 in the preferred embodiment is formed of metal and has a plurality of spaced projections or legs 38, 39 and 40 which engage the end face 15 of the bobbin case in spaced relationship. One of these legs, as for example, the leg 38, has a downwardly extending extension, such as 41, which is adapted to be received in any one of a plurality of spaced recesses or openings 42, provided arcuately upon the end face 15 of the bobbin case. I i

It will be apparent from the construction just described that the force exerted by the portion 29 upon the thread 27 and hence the tension imparted to that thread may be varied by turning the nut member 37 and that this can be readily effected by engaging one. or more of the legs, 38 to 40, with the fingers and rotating the member thereby. In this operation, the projection 41 will snap from one to the other of the openings 42 Without difficulty since the projection 41 and the depth of the recesses or openings 42 were not such as to hinder rotation thus applied. The projections and recesses are,

however, sufficient to retain the nut member 35 against deleterious rotation as a result of vibration and the like during operation of the sewing machine. Consequently, the tension exerted upon the bobbin thread may be readily adjusted and this tension will be retained during operation of the apparatus.

The range of tensions provided by adjusting the nut member 35 can be made sufi'iciently large for all desired operations by suitable selection of the pitch of the threads on the extension portion' 18 and in the nut member 35. Moreover, the extremes of the predetermined range of adjustments provided by the mechanism here disclosed can be adjusted by loosening the nut 20, turning the hub member 19 relative to the casing 13, and then tightening the nut 20 in the new position of the hub member. It will be apparent that this operation 1 calibrates the range of force exerted by the tensioning means through operation of the member 35 since the nut 35 accounts for its complete range of adjustment through less than one complete revolution. 7

The resilient member 37, in addition to acting as a means by which the nut member 35 may be readily adjusted and retained in adjusted position, also serves as a shield or cover preventing the thread from the bobbin becoming entangled with the tension member 28 or the adjusting nut 35. This is achieved by having the leg portions 38, 39, 40 of the member 35 engage at either face of thebobbin case interiorly of the raised portion or rim adjacent the periphery of the end face 15 and by having the upper portions of these legs extend coplanar with or slightly abovethe end of the nut and screw, as shown in Fig. 2. Hence as the thread passes over the bobbin case during operation of the machine it is guided by the raised rim of the bobbin case and by the legs 37, 38 and 39 so as to pass smoothly up and over the nut 35 and the threaded portion 18 without catching thereon.

It is believed that the operation of the device will be apparent from the description of the construction thereof. In review it is therefore sufficient. to note that, in using the apparatus, a bobbin 14 with the desired type and color of thread 27 is selected. Then the bail member 21 is moved to extend substantially parallel with the hub member 19 and the bobbin 14 is inserted within the bobbin case 13. With the bobbin 14 thus placed, the bail member 21' is moved to its radial position, as shown in'Figs; 2, 3 and 4, where the planar surfaces 25 and 26 will frictionally retain the bail member 21 in place, so that the bobbin 14 is prevented from accidental displacement from the bobbin case 13. The loose end of the thread 27 is preferably led from the bobbin 14 through the opening in the end wall 15 of the bobbin case and beneath the tension member 28 before the bobbin is fully placed Within the bobbin case, although this operation can, if necessary, be effected thereafter. The tension upon the thread thus extending between the member 17 and the tension member 28 is then adjusted to the selected value by moving the nut member 35 through the engagement of the fingers of the member 37, the tension being retained by virtue of the projection 41 thereon snapping into a corresponding one of the recesses or openings 42.

The operator then grasps the bobbin case by means of the member 37, and with the interior of the hub 19 aligned with the shuttle stem or pin 12, pushes inwardly onthe bobbin case thus causing the ends 22 and 23 of the bail member 21 to snap into the groove 24, whereupon the bobbin case and bobbin are retained in proper position for use. The bobbin case may be removed, when desired, by simply pulling outwardly thereon and the bobbin removed from the case by reverse movement of the bail member 21.

It will be evident from the construction of the preferred wide range without the need of special tools or the like.

Furthermore, the construction is such that the parts may be cheaply and easily manufactured and assembled without the need of expensive equipment or specially skilled help. Moreover, the mechanism is simple and reliable in operation and provides a heretofore unattained range of thread tensions for a rotary bobbin.

Although the present preferred embodiment has been described in specific language and considerable detail, it will be understood that numerous changes may be made in the construction thereof by those skilled in the art. Therefore, the details here illustrated and described are intended only as being illustrative of one specific embodiment of the invention and are not to be construed as limiting the latter except as may be required by the spirit and scope of the appended claims.

Having thus described the invention, I claim:

1. A bobbin case adapted to be used with the rotary shuttle of a sewing machine and which shuttle is pro-- vided with a center pin on which the bobbin case is adapted to be mounted and which pin is provided with an annular groove adjacent its inner end, said bobbin case comprising a cup-shaped member having an open end andv a closed end provided with a radially extending rigid finger, said member being provided with a tubular centrally and interiorly located hub extending from the closed end thereof to beyond the open end thereof and provided adjacent its free end with diametrically aligned openings therein and adapted to be sleeved upon the center pin of the rotary shuttle when said member is mounted therein in inverted position, a resilient bail having inturned aligned free ends extending through said diametrically aligned openings in the hub and being adapted to be received in said annular groove on said thereto a portion of said closed end and overlying and en gaging said rigid radially extending finger so as to exert a.

frictional force on a thread extending from a bobbin mounted in said bobbin case and passing between said tensionmember andsaid finger, and an adjusting member connected with the closed end of the cup-shaped member and overlying and engaging the said tension member for varying the spacing between the said tension member and the said portion of said closed end of said cup-shaped member to thereby vary the frictional force exerted upon the thread by said tension member.

2.. A bobbin case as defined in claim 1 and wherein said closed end of said cup-shaped member is provided centrally thereof with an opening while said hub at its inner end is provided with a threaded portion extending through said opening and secured therein by a nut, said threaded portion also-forming the mounting for said tension memberand saidadjusting member.

3. A bobbin case. as defined in claim 1 and wherein the said bail and said hubv are provided with cooperating frictionally interengaging surfaces which frictionally retain the bail in a position such that it extends radially from said hub thereby retaining a thread bobbin in said case when the latter is removed from the shuttle.

4. A bobbin case as defined in claim 1 and wherein the closed end of said cup-shaped member is provided with a central opening while said hub has a threaded extension portion at its inner end projecting through said opening, a nut on said threaded extension securing said hub to said cup-shaped member, an elongated resilient thread tension member providedwith an opening through which said threaded extension portion of the hub extends, said tension member extending diametrically over a part of said closed end with a portion of said tension member spaced outwardly fromsaid closed end and another portion engaging said finger for exerting a frictional force thereon, means on said cup-shaped member engaging said tension member to prevent rotation of said tension member, and an adjusting nut member threaded upon said extension portion of said hub outwardly of said tension member and engaging the latter for varying the spacing between said first mentioned portion of the tension member and said closed end of said cup-shaped member to vary the frictional force exerted by the tension member uporrsaid finger.

5. A bobbin case for a sewing machine comprising a cup-shaped member having a closed end provided with a central opening, a central inwardly extending hub member for said cup-shaped member having a portion extending through said opening, means for securing said hub member to said cup-shaped member, an elongated resilient thread tension member provided with an opening through which said extended portion of said hub member projects, said tension member having a portion extending over said closed end and spaced outwardly therefrom and another portion engaging said closed end and adapted to exert a frictional force on a thread extending from a bobbin mounted on said hub member and passing between said tension member and said closed end, means on said closed end of said cup-shaped member engaging said tension member to prevent rotation of said tension member, and an adjusting nut member threaded upon said extension portion of said hub outwardly of said tension mem ber and engaging the latter for varying the spacing be- 1 tween said first mentioned portion of said tension member andsaidclosed end of said cup-shaped member.

6. A bobbin case for a sewing machine comprising a I cup-shaped member having a closed end providediwith a radially extending rigid finger, said closed end having a central opening, a central inwardly extending hub member for said cup-shaped member having a threaded extension portion projecting through said opening, a nut on said threaded extension securing said hub member to said cup-shaped member, an elongated resilient thread tension member overlying said nut and provided with an opening through which said threaded extension portion of the hub member extends, said tension memberextending'diametrically oversaid closed end and having a portion spaced outwardly'from said closed end and another portion engaging said rigid radially extending finger so as-toexert a frictional force on a thread extending from a bobbinmounted' on saidhub member and passingbetween'said tension member and said finger, means on said closed end of said cup-shaped member engaging said tension member to prevent rotation of said tension member, an adjusting nut memberthreaded-upon said extension portion of said hub member outwardly of said tension member and engaging the latter for varying the spacing between said first mentioned portion'of the tensionrnember and said closed end of said cup-shapcdmember, said adjusting nut member being provided with a plurality of radially extending arms overlying portions of said'closed end of said cupsnaped member, and cooperating interengaging means on said closed end of said cup-shaped member and (mat least one of said arms to releasably maintain the adjusting nut member in adjusted position.

7. In a sewing machine having a rotary shuttle provided with a center pin having an annular groove therein adjacent to the point. of, attachment between said center pin and. shuttle and upon which center pin a cup-shaped bobbin case having interiorly thereof a central hollow hub is adapted to be removably sleeved over said pin, the improvement which comprises providing in said hub an opening adapted to overlie said annular groove in said pin, a resilientdetent having a portion extending through said opening and rotatable therein and engageable in said groove in said pin and another portion extending radially from said hub and engageable with an end face of a thread bobbin positioned in said case, said detent and said hub havingfrictionally engaging cooperating surfaces maintaining the second named portion of said detent in a radial position relative to said hub to retain the thread bobbin in-said. case.

8. In a sewing machine having a rotary shuttle provided with a center pin having an annular groove therein adjacent the point of connection of said pin with said shuttle and upon which pin a central interior hub connected to the bottom, of a cup-shaped bobbin case is adapted to be removably' sleeved over said pin, the improvement which comprises providing in said hub a pair of diametrically aligned openings adapted to register with said groove when said hub is sleeved on saidpin, a resilient U-shaped bail member having the free ends of its legs ir'turned and extending throughsaid openings with a frictional engagement with the walls of said openings and extending into said annular groove, said bail member being swing able from a position extending radially of said hub wherein it will engage anv end face of a thread bobbin mounted insaid caseand on said hub to a position wherein it extends longitudinally of said hub to permit the thread bobbin to be removed from said. hub and case, said hub and the legs of said bail member having cooperating surfaces which frictionally engage when said bail member extends radially from said hub to retain the bail member in, such position.

References Cited in the file of this patent UNITED STATES PATENTS 341,333 Junker May 4, 1886 346,281 Heberling July 27, 1886 601,837 Miller Apr. 5, 1898 608,552 Mack Aug. 2, 1898 814,341 Abercrombie Mar. 6, 1906 8.91.028 Atwood a June 16,- 1908 934,869 Winkel Septf21, 1909 974,309 Thayer Nov. 1, 1910 974,757 Dow Nov. 1. 1910 2,034,506 Colegrove etal. Mar. 17. 1936 FOREIGN PATENTS 115,077 Germany Nov. 19, 1900 

